This invention relates to audio apparatus for the reproduction of selected sound recordings from a plurality thereof included in a common sound track unit and more particularly to such an apparatus which may be used with audio visual apparatus adapted to enable the user to select any one of a group of photo-images for viewing or to sequentially view the photo-images of such group in any desired order with the audio production of a lecture or commentary relating to each photo-image being automatically selected from a corresponding group of sound recordings.
In order for audio-visual apparatus to be useful for instructional purposes, it is necessary that such apparatus be simple and convenient to operate, small, rugged and lightweight for portability, and inexpensive to manufacture and maintain.
It is an object of this invention to provide ,for use in apparatus of the type described, disc type records for sound recording which are mounted in rugged units for storage and use.